A z score tells how many standard deviations a value is from the mean
A positive z score means the value is above the mean
A negative z score means the value is below the mean
A z score of 0 means the value is equal to the mean
A z score of 1 means the value is 1 standard deviation above the mean
A z score of -1 means the value is 1 standard deviation below the mean
A larger absolute z score means the value is farther from the mean
A z score near 0 means the value is close to the mean
A z score can be used to compare values from different distributions
A z score can help identify unusually high or low values
A z score around 2 or -2 is often considered unusual
A z score around 3 or -3 is often considered very unusual